Spiral molecular structures the basis of life

Spiral Molecular Structures
the Basis of Life.

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SPIRAL MOLECULAR STRUCTURES
THE BACIS or LIFE.

(Second Edition)

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oy
C^.rl F. Krafft,
Washington., D. C.

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■ (-i

1928

1.

SPIRAL MOLECULAR STRUCTURES
THE BASIS OE LIFE.

Introduction.

Thoro arc certain iDiological proc3GSGS such
as growth, va,riation, and reproduction, which are
exhibited by 3V :ry living organism, regardless of
its rank in the plant or animal kingdom. These
processes establish in nature a sharp line of
demarcation between living and ncn-living things,
since none of the phenomena of physics or chemistry
exhibit anything that is similar or analogous to
these fundamental life processes.

Biological grov;th involves not only the
accretion of tissue-building material, but also
many remarkable chemical transformations which
take place during metabolism, as well as the
dev elopmierit, in m.ost cases, of highly complex and
heterogeneous structures. The nearest approach to
this in the inorganic world is the growth of crystals,
but crystal growth produces neither the remarkable
chemical transformations nor the complex structures
which often result from biological growth, not to
mention several minor differences such as the
polyhedral form of crystals as distinguished from
the rounded form of most living organisms, and
the hardness of crystals as distinguished from the
softness of most living tissues. The differences
betv^een crystal growth and biological growth are
so manifest that it seems hardly fair to assign
them to the sam.e category, and much less to pro-
pose the one as an explanation for the other.

2S904

2.

Biological variation differs from all inor-
ganic changes and motamorphosos in that the newly
acquired structuroc cxort a directing influence
upon the future grov/th of the individual, and are
perpetuated "by a process of heredity.

Biological reproduction is like-zrisG so dis-
similar from any of the other processes of nature
that it seems impossible to establish even the
remotest analogy, and much loss to attempt to
explain it on the basis of any of the known phe-
nomena of physics' or chemistry.

These fundamental life processes are exhibited
just as fully and completely by the simplest bacteria
as by the highest plants and animals* All living
organism.s, notv;ithstanding their diversity of form
and appearance, must possess something in common
which gives rise to that peculiar characteristic
called "life".

If th 3 fundamental life processes are due
primarily to some specific configuration of
tissues or membranes, then such configuration
would have to occur in every living organism,
including the simplest bacteria. Y/e find in
nature many structural uniformities which occur
more or less extensively among certain species
of plants and animals, but these are the result
of evolution and v;ill be found to disappear as
we go down the scale of plant or animal life.
Even the chromosomes which occur in the cells of
all higher plants and animals have never ^03on
observed in any of the bacteria, and therefore
cannot be regarded as th-e primary and original
cause of the fundament^-! life processes. It
would not be justifiable, in the absence of
experimental proof, to assume that chromosomes
or similar structural complexities exist in
bacteria, merely because they have been observed
to exist in the cells of the higher plants and
animal s .

3.

That the fundamental life procossss must
"be duo, either wholly or partly, to specific
chemical structures is generally admitted, hut
there is a pr availing opinion that the molecular
structures which are necessary for this purpose
must be extremiCly complex. The failure of all
previous efforts to devise some type of molecular
structure which would function in a manner
similar to the fundamental life processes does
not, hov/ever, prove that the solution of the
problem must lie in the direction of extreme
complexity. The complex molecular structures
of which the higher plants and animals are
comiposed have developed gradually in the course
of evolution, and the fact that they are necessary
for the proper physiological functioning of the
particular organisms in vjhich they now occur.;-
does not prove that they v^ere also the original
cause of the fundamental life processes in the
more primitive ^'xrganisms from v/hich these higher
plants and animals have developed. If extremely
com^plex molecular structur3S v-^ere necessary for
life of any sort, then it vfould he highly im-
prchabl e that life could ev 3r have originated
spontaneously.

4.

The Ch3mic^l Basis of Life.

If life cannot bo due, prirr.arily, either to
specific arrangaments of tissues or inemToranes or
to extrernely complex molecular structures, then
it must be due to some comparatively simple
principle of chemistry vrhich has not yet been
discovered. To find a cluo to this we must in-
vestigate the molecular structure of prot3ins,
because those constitute practically all the
structural material in the bodies of the simplest
unicellular organismiS after removal of the vat 3r,
Althougl': small amounts of fats ar ^ also present,
yet these do not constitute structural material
but appear to be merely the by-products of
certain kinds of protein metabolism.

Protein substances, upon hydrolytic decom-
position, always yield a mixture of amino acids
or their dik etopip erazine derivatives. To the
alpha carbon atom of these acids thsra is alv/ays
attached one amino group and one hydrogen atom,
and usually also a more complex group, so that
they may be represented generally as foilov/s:

ITH2-CKR-CO-OH.

The structural formulae of the more im-
portant ar;:ino acids are as follows:

5.

Glycine COOH

t

HCH
»

Alanine

Serine

ITHo

Cystine HGOC

t

HgN

Aspartic acid

COOK

CK3-

-CH
f

KKg

COOH

t

HOCH2— -

CH
1

ITH2

COOH

T

.0 -S-S-II

oC — CH
^ 1

1^2

COOH

'OC-CH2-

-CH

KH2

Proline CGCH

CH^ »

'2 ^-

HgC

CH-

Oxyprol ina

HOCK

6.

CH.

CH.

COOK
f

CH
»

Glycine-prolin 3 anhydride

(E. A"b4erhald*n & 15. Komrn,
Z. physiol. Ch-TH., 145, 308, 19.^5.)

Hp,Q

K^C

/

CO — CH

/

TJ

\

CH —

CH.

^

UK

/

CO

Glutamic acid

HOOC-CHg-CHg-

COOK

!

■CH
t

ITK^

Ornithine

COOK
f

NHg-CK^-CHg-CHg— CH

rlH

o

7.

Histidino

CCOH
/ C-CKo — CH

hi: I " »

CH "^ "^

Arginins

ITH

Caprins CO OH

f

CH3-CK2-CH2-CH2— CH

ITHo

Lysin3 CCOH

!

H2N-CH2-CH2-CK2-CH2 — CH

^2

Valina COOK

f

" CH—CK

CH3 .

CH3

\

jMHo

COOK

>TH^^ »

C-m--CH2-CH2-CH2--CH

L 3Ucin3

8.

COOH

CH.

CH.

CH-CKo —

2

CK
t

Iso-] 2ucin3

CCOK

CK

^-.

CH-

CHs-CK^'-

OH

T.TTT

Ph anyl - al r.,nin 9

H

HC

- C

C

C '^'
H

.C-CKg-

COCK
f

CH
f

Tyrosma

H

HOC

C '■■

C -
H

H

'I

*^

C
H

C— Uj.Xo'

COOH

■CH
»

9.

Tryptophp.n 3

H COOK

- C :.,^ '

HC ^ '^- Q- -• C~CHp — OK

ii i if "^

HC /-C . CH

H i]H

t

Leucin3-gluta,!i]ic «.cid .anhydrida
(p. A. L?vin3 & W.A. Beatty,
Ber. 59, 2060, 1906.)

^, CO — ITIi^ ^ CK3

HOOC-CHp-CK^-CH'" ^Z. CH-CHp-CH ^

^ ^ -^ i:tT CO -^ ^ -^ CH3

Valyiz-leucine

(?:. Abderlial den, Z. Physiol. Oh 3m.,

131, 284, 1923.)

CH^ .CO — :iH .^ ^. CH3

^^ CH- CK : '^ CH- CHg - CH '"

CH3 "" ""■mi — CO -^'^ ^^^^ CH3

Leucine anh^.^dride

(E. Aoderhalden & K Punk,

Z. physioi. Che-T,. 53, 19, 1917.)

CH^ CO — KH^ ,,.CH3

'"'^ CH- CHp - CH '^' ^ CH- CHo - CH "

CH^-^' ^ irn — CO "" ^ "^"CiHj

10.

Th3S3 amino acids will readily cond-Dnsc,
v/ith the 3liTnination of water, to form eithsr
chain structurss known as polypeptides, or ring
structures knovn as dik etopiperazines .
(Smil Fischer, Unt 3rsuchung 3n liber Aminos^iuren,
Polypeptide, und ProteSne, 1899 - 1906;
Plimr::er's Chemical Constitution of the Proteins,
Monographs on Biochemistry, Longmans, 1912)

3 NHg-CRK-CO-OH =

im2-CRH-C0-!'^-CRK-C0-lTK-CRPI- CO-OH + 2 HO;

2 NHg-CRH-CO-CK =

CRH CO,,^

HN ■ ^^IIH + 2 H9O

"^•CO • CRH--^''

^

Since protains constitute the principal
structure-lDuilding food for animals, and upon
digestion are decomposed into amino acids, in
v^hich form th 3y are assimilated by th 3 tissues,
it is gensrally thought that the phenomenon of
grovjth involv 3S condensation processes of a
similar character.

The frequent occurrence of diketopiper-
azine rings among th 3 disintegration products of
proteins seems to indicate that this may be the
form in which the alpha am.ino acid groups occur
in nature, but a fatal objection to this thsory
is that diketopiperazines cannot grow by con-
densation with additional amino acid molecules.
If our purpose is to solve th 3 problem of life,
then the biological side of the probl 3m must be
given full consideration, and we should have but
little patience with any theory which explains
only the chemical but not the biological facts.

II.

The polypeptide thoory teaches that the
amino acid groups occur in nature in the form of
long polypeptide chains. This theory offers at
least a partial explanation for the phenomenon
of growth, as well as for structural variation,
hut in its present form is inadequat3 in th^\t
it does not account for that definite morphology
which is possessed "by all living organisvns, nor
for spontaneous division with the transmission
of hereditary charact sristics to the progeny.

There is, however, another type of struc

ture, namely the helical spiral, which retains

the 3ssential characteristics of both the ring
and the chain.

12.

Polypoptids S-pJrals.

If W'3 as sum 2 that th 3 val?nci3S of the
carbon ato^ ar3 arrang3d like th s corners of a
regular tetrahadroE, and that th 2 three val3nci9S
of tri-val ent nitrogen in amino compounds are
about 3qual]y distributed around an equatorial
circle, (vhich arrangement appears to b :- the
only on ^' that is consistent with rill knov/n
chemical facts,) then the polypeptide^ chain may
be coiled around on itself so as to form a "•

h el i c al sp i r al h av i ng sub s t an t i al 1 y th 3 s am 3
di^jT:]eter as the diketopip erasine ring.

KO

^

/

L J C7/

H-N

0

\

C

HO

'/

n

/ \

R H

/ \

R K

A polypeptide spiral in KaCl solu

1

33.

Th D nitrog?n atoms v.'ill appear in tv/o rovs
on opposit3 si^.3s of th3 ppiral , and the co^npl 3X
tid3 chain? r3pr3S3ntod by th s R's in th ? previous
equations, as well as th 3 carbonyl gr-oups, wil]
1 i.k 'Wis 3 arrang3 th3Tnselv3S along other diaTri3tri-
cally opposite lines. Chsrr.ic^J. union will probably
tak3 place b3tw3en th 3 succes?iv3 nitrogen atoviis
by virtue of th3ir fourth and fifth valenci3S,
and p3rhn.ps also betv^een th 3 successive carbonyl
groups in the manner sho^.vn. The nitrog3n atoms at
th 3 3nds of the spiral will probably units with
th 3 ions of inorganic salts, th 3 pr3Senc3 of which
is n3C3ssary for th3 nourishmsnt of all living
organisms. It will b? found upon actually con-
structing this spiral of atomic models that thECs
is •■^mpl ? room for th3 complex sid3 chains R if the
fourth valency of th 3 alpha carbon atom is occupi3d
by hydrog3n, but that th 3 pr3sence of rnoT 2 complex
groups in this position would make the spira]

structur3 impossible. We find, hov;e-B3r, that the
decom.position products of proteins always have a
hydrogen atom in this position.

It will be observed that the polyp 3ptide
spiral in the accompanying diagram has an 3xposed
amino group at one end, and an exposed carbonyl
group at the other end. Th eor 3ticall y it appears
that additional amino acid radicals could be add 3d
to eithsr end of th 3 spiral, although there may
be some at pr3sent unknown reason why growth can
take place at on 2 end only. A spiral with an
expos ?d amino group at th j free end may be d3sig-
nated as positiv3 { + ), and on3 with an 3xposed
carbonyl group at the fr3G end as negative (-).
A distinction should also b j made betw3en right-
hand 3d (r) and left-handed (l) spirals.

14.

Th 3 similarity in forTj and app 3aranc : of a
polypeptide spiral to a "bacillus or a spirillum
will be apparent. It should be capable of graving
-endwise by condensation with additional amino acid
radicals, and as long as tho spiral form is main-
tained the structure will possess definite mor-
phology. It must remain permanently right-handed
or left-handed which appears to account for the
optical activity always s^±Libited by substances
obtained from living organisms. It should be
capable, during growth, of acquiring different
arrays of side chains upon being nourished with
different kinds of amino acids, and thus exhibit
the characteristic of variability. It would not,
however, upon division, be capable of transmitting
to its progeny any permanently inheritable ch ' rac
teristics, and can therefore not be regarded as a
complete living organism.

15.

The Linking of Pol ypeptide Spirals

Since th ^ distance between the centers of
adjacent carbon atoms is about 1.54 x 10"® cr. ,
the diameter of a pol;>'p ept ide spiral, as measured
between the centers of the •^toms, would be ^bout
?.l X 10~° cm. It will therefore require several
hundred spirals arranged side by side to produce
an organism^ at large ^s the sm.a]lest visible
bacillus, whijQh m2asure3 about 1000 x 10"^ cm
in diameter. In order that the organism may
possess definite individual characteristics, these
spir'-Qs would hav b to be coupled together in some
permanent m.anner, but after they are thus coupled
tog 3th er, they will have a tendency to preserve
their arrangs-ment throughout growth, and if trans-
verse fission occurs, each portion would hav3 to
continue growing according to the originpJ pattern,
There will thus be exhibit 3d, in the simplest
possible mann3r, a proc3ss of inheritanc3 by vmich
parental characteristics are preserved throughout
growth and transmitted to th 3 progeny.

It appears that there ar 3 only a limited
numbsr of ways in which adjacent spirals can
be connect 3d tog3th3r. The connecting ccm.plexes
must be conparat iv 3I y simple, b?caus 3 if more
than a cert^^in number of int srmiDdiat 3 atoms are
pr3S3nt their m.ovBmonts v:ill no longer be
definit3ly coordinated so as to form th 3 r required
int3rmediat3 structures, but will b3 m5r3 or 1 3ss
at random. In ord3r to d?t3rmin3 the nature of
thes3 conn3cting complexes, th 3 use of atomic
models is r 3ccm.mend 3d, b'^caus3 the probl 3ms
encountered hsre ar 3 structural rather than
dynam.ic .

Th3 form of
most fraquontly in
conn Oct ion lD3twien
of a C3ntra] ^^arbo
which aro usua]ly
atoms of amino aci
from such connscti
a study of protein
two typ^s of such
pro t 3 ins .

16.

connecting complex which occurs
natur3 appears to be a triple
thrcD adjacant spirals by m, 3-^ns
n atom. The compl 3X groups
attach 3d to the alpha carbon
ds arc 3vid3ntly the fragments
ng comp] exes. It appears from

d 3composit ion products that
tripl 3 connections occur in

Leucine, phenyl -al an in e, and tyrosine have
a triple junction at th 3 gamma carbon atom, with
an intermediate -CHo- group between this triple
junction and the -CH IHig-COOH group. The complete
tripl 3 junction, (assuming it to be the same on
all thr3e sides,) tog 3th er with one-half of each
of the three adjacent spirals, will therefore
app ear s omi ewh at as follows:

OC

MI

\

\

CH

CH^

CH

CH,

CK,

1^: — CH

CH

CO

CO

HF

A triple junction of the gamima-gamma-garrima type.

17.

which liii r P^°^-:^^y ^'-^- typ. of trip! 3 junction
whichwill form most rs-'^.dily in naturo. b^causo if

thev wn,nT>;^'^'; "'''2- groups W3re introducad
they would have too much f r -dom of mov 3m 3nt to
produce the triple junction spontaneously. Hydro-
carbon chains will not react with 3ach oth^r ^f
they are capable of movement at random in any^

wnnTr^""'''.^''? ^^^^ '" ^^^^ ^^' condition which
would exist at any point biyond th3 gamma carbon

-^A. "^^* 2" "^^^ 0th 3r hand, we omit some of th -
xntarmediate-GHg-^- groups and attempt to form the
triple junc-:ion at the b3ta carbon atom th -
spirals will have to b3 brought so cl.os3 togeth-r
that there would probably be considerable repul-
sion betwaen them due to th 3rmal vibration of th -
atoms. Such a triple junction could prooably not
form spontaneously unl 3ss the spirals were crowded
together from the outsida, but the prssence of
substances like iso-leucins and valine ^Tiong th -
decomposition products of proteins seems to show
tnat triple junctions of the beta tyiDe do occur
at times.

The existence of both beta and g=^mma junc-
tions in the same prot 3in is indicated by the
occurrence among protein decomposition products
of^ substar.ces like val yl -1 eucin 3 which contains
a beta junction at one end nf the rnol ecul 3 and
a g^mma junction at the other end.

If W3 connect togeth3r a lar/^3 numb 3r of
spirals by means of triple junctions of eith sr
the beta or ths gamma type, th ay will form
coll ectiv sly a cluster of hexagonal compartments.

18

The cellular structure of proteins.

In living tissues these will "be filled with water
or dilute salt solution, and it will be observed
that the vacant spaces in these compartments have
a combined cross-s ection<al area equal to about
three-fourths of the entire area of the figure.

The hexagonal form of compartment is believed
to be the form which occurs most frequently in
nature, because the h3xagon is one of the few
figures which when duplicated will completely cov 3r
an area of indef init olsize. The only other possi-
bilities are quadrilateral and triangular compart-
ments, but as these would require the coupling
together of four or six spirals respectively,
it is considered highly improbable that they occur
to any great extent in nature. It is doubtful
whether connecting complexes between six spirals
could form spontaneously und 3r any conditions,
but connecting complexes between four spirals
could probably be formed occasionally as follows:

19.

A A

CH — CH

CHp

CH,

CH

CH

A cluster of thr-ae polypoptide spirals with
a coTi]pl-3t3 tripl3 junction at th 3 canter ought to
possDss all th 3 fundarn Bntal characteristics of
life, provided it is equipped with a stable outer
structure. A group of three hexagonal compart-
ments as illustrated on tha precedirg page could
probably not exist in nature becausD each com-
partment would have three exposed corners which
would rander it very vulnerable. Regardless of
how many additional compartm3nts W3 add to this
structure, the m^aximum numb sr of exposed corners
can nevsr b ■; less than two. But at th« surface
of the organism th3re is really no nscessity for
confining ourselves to the use of hexagons. If,
for example, we form th 2 surface structura of
pentagons instead of hexagons, the number of
exposed corners on aach compartmant would be re-
duc 3d to one, and our organism v;ou] d appear in
cross- section somewhat as follows:

20.

Cross-section nf a simpl 3 living orgnnism,

Perhaps cystine, which occurs in small
aTTiounts in the dGcompcsition products cf ill
proteins, forms part cf this surface structure.

21.

Direct Ch-smical Union "b 3 1 ;v o jn Sp i r "^J. r- .

Ws hav3 har-atnl'crs aGSurnad that c^nnDction
"between adjacent spirals t.ak^s plac3 only through
the hydrocarbon side chains attached to the alpha
carbon atcms. This is undoubtedly the priir.ary
mode of connection, but af t :r tv/o spirals are
thus connected together there may bj a secondary
connection between th 3 arnino groups of on^ spiral
and th3 carbonyl groups of the other. If both
spirals have the sa:!ne dirsction of twist, the
amino hydrogsn cf on 3 spiral will b3 posit ion jd
directly opposite the carbnnyl cxyg i^n of th3 other
spiral, so that there will bo a tsndsncy for wat 3r
to split ^ff, leaving the amino nitrogen to combine
directly with the carbonyl carbon. In this manner
there m.ay be produced either thj pyrrole or the
pyrimidine ring, depending on wheth3r the primary
connection was of the beta or of the gamma type.
As shcv\rn in the follov/ing diagrams, various dif-
ferent configurations can b3 produced by joining
adjacent spirals directly to 3ach other:

V-r^'

op

A carbonyl carbon atom should "be abl o to
units in this mann2r with two nitrogsn atoms of
an adjacent spiral, and since it is already joined
to one nitrogen atom of th ? same spiral, thare will
bs produced in this manner th? guanidine complex
which occurs at one 3nd of the arginine rKolecuJe.
The three intarmediate -CHq* groups of the arginine
molecule are exactly the number that would occur
in passing over to the next adjacent spiral if the
intermediate junction is partly of the beta and
partly of the gamma type.

HCH

CH

OC

im

Arginine in situ.

Conclusion.

The c^rractness of the above hypothesis
depends in n. ln.rge measure on wh eth 3r we were
justified in -ai^Jcing the assumption that the
fundamental, life processes ar 3 inherent in the
molecular structure of the proteins, and are net
primarily dep3ndent on any specific physical
heterogeneity. This assumption is clearly cr^n-
trary to orthodox theories which attribute just
as much importance to the physical heterogeneity
of protoplasm as to the chemical comstitution
thereof, but the failure of orthodox theories
tc account for and explain th 3 fundamental life
processes should be sufficient justification for
attempting the solution of the problem on a
new bas^.

The molecular structure of proteins v^ill
probably never be established conclusively by
chemical analysis n2one. It is, in fact, doubt-
ful whether protein molecules are of uniform size
and composition. According to the foregoing
hypothesis protein m.oleculos, when dissolved in
water or dilute salt solution probably consist of
platelets of irregular form and size which have
become separated from a cluster of hexagonal com-
partments. The methods of analytical chemistry
can tell us only what the fragr^ients of protein
structure are and what the elementary composition
thereof is, In order to find out how these frag-
ments were joined togethsr we miust take into
consideration the principles of biology, although
after a certain scheme has been suggested, we
may determin3 the probable correctness th3reof
by comparing the elementary composition of such
hypothstical structure with that found experi-
mentally.

24.

All proteins, (v;ith the oxc option of prct-
R-mines and histonos, ) hav::; apprcxitnat oly tho
following p3rc3ntag3 ccTnposition;

Carbon Hydro g2n Nitrogen Oxygon Sulphur
50-55 6.9-7.3 15.0-19.0 19.0-24 0.3-2.4

If WD takG, as a roprosentativ o sample of
our hypcthotical substance, a compl ot o tripla
junction of the gamrna-gamrna-gi^jTiTTia typo and cn3-
half of oach of th 3 thr^e adj ac 3nt spirals, th on
the orapirical formula th3r3for may b: dorivod
as follows:

/co\

H3
This will give the following percentage composition:

Carbon Hydrogen Nitrogen Oxygon
53.8 5,8 18.8 21.5

The values thus calculated are in fairly
accurate agreement with the exporimental values,
except that the hydrogen is slightly low, but that
is just what would be expected because of the
difficulty of obtaining proteins in perfectly
anhydrous condition. Another possible explana-
tion for the low hydrogen percentage is that the
protein molecule in v/at er solution may consist ^f
only a thin sheet t^iken transversely of the ax 3S
of the spirals, so that many additional hydrogen
atoms or hydroxyl groups v/ill b^ requirod for
combination with the free ends of the spirals.
For exo.mpl e, if wo include only tw^ additional
hydrogen atoms in our th3cr?tical formula, the
porcantago of hydro g on will bo brought up to the
values obtained 3xp or im entail y.

:5,

If v; D n,ssu-ai^ the tripl 3 juncticn tc "be only
tv/c-thirds gninir.^.. and on-3!-third bota, th Dn the
porccntago composition will b 2 -is follows:

Carhrn Kydrcgcn Kitrcg an Oxygon
52.1 5.2 20.1 23.1

Inst3ad of dealing vrith absoluto p 3rc ant ag ds
of th3 various elDments, it is b ott ^r to deal
with ratios of carbon tn nitrogen, bocauoo the
ratio of th es a two values will b l^ un-^ffected by
varying ^^jmounts of v^ater that may be present, cr
by the extra hydrogen that rno,y be attached to the
free ends of the spir-^2s.

From the above theoretical d'lta wo obto.in
the following ratios of carbon to nitrogen:

With triple junctions of the

g 'iTDTn a - g ^xn-ra -'.- g arnm a t yp e ,

With trljftl e juncticns of the
b :^t a- g aTP.m a- g omrn a typ e ,

With quadruple juncti':ns

of the type:

2.86

2.59

^

CK — CK

2.14

X.

With quadruple juncti'-ns

of the type

CH

CH"

CH2
CHo

3.00

27.

No att 3Tnpt h-i.s bo on mad j horjinabrva to
expl'iin the chrcT.oscir.o mechanism in det'^.il.
ChrcrnoGoiTGS dc not occur in the simplest
organisms such as the bactaria, but app 3'\r to
bo th3 first stago in ovoluti^n to high or
typos, whorsas the purpr^so of th o prosont
treatise is to oxp] ain 1 if o processes only
in so far as they aro of universal occurrence
and common to all forms of life.

.-7

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